Vulnerability · Published Aug 20, 2026 · Assigned by GitHub_M
CVE-2026-49825lxml: javascript: URL bypass in Cleaner via xlink:href
High 8.2
In plain English
A high-severity cross-site scripting in lxml_html_clean from fedora-python. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 22% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official description
lxml is a library for processing XML and HTML in the Python language. Prior to 6.1.1, link attributes in ``lxml.html.defs.link_attrs`` were missing ``xlink:href``, which can be used for URL bypass attacks in embedded SVG/MathML/etc. content. This vulnerability was fixed in lxml 6.1.1 and lxml_html_clean 0.4.5.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:8 | python3-lxml | 4.2.3-5.el8_10 | ALSA-2026:67943 |
| AlmaLinux:9 | python3-lxml | 4.6.5-3.el9_8.1 | ALSA-2026:66204 |
| AlmaLinux:9 | python3.12-lxml | 4.9.3-2.el9_8.1 | ALSA-2026:66203 |
| Debian:12 | lxml | 4.9.2-1+deb12u1 | DEBIAN-CVE-2026-49825 |
| Debian:13 | lxml | no fix listed | DEBIAN-CVE-2026-49825 |
| Debian:14 | lxml | 6.1.3-1 | DEBIAN-CVE-2026-49825 |
| Debian:13 | lxml-html-clean | no fix listed | DEBIAN-CVE-2026-49825 |
| Debian:14 | lxml-html-clean | 0.4.5-1 | DEBIAN-CVE-2026-49825 |
| PyPI | lxml-html-clean | 0.4.5 | GHSA-4jhm-jv67-739f |
| PyPI | lxml-html-clean | 0.4.5 | PYSEC-2026-2614 |
| Rocky Linux:8 | python-lxml | 0:4.2.3-5.el8_10 | RLSA-2026:67943 |
| Rocky Linux:9 | python-lxml | 0:4.6.5-3.el9_8.1 | RLSA-2026:66204 |
| Rocky Linux:9 | python3.12-lxml | 0:4.9.3-2.el9_8.1 | RLSA-2026:66203 |
| Ubuntu:22.04:LTS | lxml | 4.8.0-1ubuntu0.1 | USN-8897-1 |
| Ubuntu:22.04:LTS | lxml | 4.8.0-1ubuntu0.1 | UBUNTU-CVE-2026-49825 |
| Ubuntu:24.04:LTS | lxml | 5.2.1-1ubuntu0.2 | USN-8897-1 |
| Ubuntu:24.04:LTS | lxml | 5.2.1-1ubuntu0.2 | UBUNTU-CVE-2026-49825 |
| Ubuntu:26.04:LTS | lxml | 6.0.2-1ubuntu0.1 | USN-8897-1 |
| Ubuntu:26.04:LTS | lxml | 6.0.2-1ubuntu0.1 | UBUNTU-CVE-2026-49825 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| lxml | lxml | < 6.1.1 |
| fedora-python | lxml_html_clean | < 0.4.5 |
Weakness: CWE-79, CWE-184 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:L/A:N
References
- https://github.com/fedora-python/lxml_html_clean/security/advisories/GHSA-4jhm-jv67-739f x_refsource_CONFIRM
- https://github.com/fedora-python/lxml_html_clean/commit/322357ac61c6cf80fcbaba53b4e92e31f3ded9f2 x_refsource_MISC
- https://github.com/lxml/lxml/commit/5927a6d5e851845140975d99b65461e255caaab0 x_refsource_MISC
- https://github.com/fedora-python/lxml_html_clean/releases/tag/0.4.5 x_refsource_MISC
- https://github.com/lxml/lxml/releases/tag/lxml-6.1.1 x_refsource_MISC